Improvement in processes for the manufacture of carbonate of soda



decomposition.

W y I arps lit. B KER; or lwI-AsnINe'roN, DISTRICT, or COLUMBIA.

j Letters Patent No. 108,088, dated October 11, 1870."

IMPROVEMENT m'PRocEss's FOR THE MANUFACTURE 'OFCARBONATE OF SODA,

HYDRO-CHLORIC ACID, 800. r

The Schedule referred. to in these Letters Patent and making part oi the same l I, Harm: MfBAKnn, oi'th e'gcity of Washington,

- iirthe District of Golumbia,haveinvented and'discov- .cred a new and useful FProcess for the Manufacture of Hydrochloric Acidand Carbonate of Soda or Garbonate of Potassa fi-om Ohloride of'Sodium or Ohlor ide of Potassium, of which the following is a speeifi cation. a

-'It has long been known that vapor of water passed over chloride of sodium in a fused condition effected mutual decomposition of the said chloride of sodiuum andwater,transformingthem into caustic soda and hydrochloric acid, but that these reactions could not be made available on. account ofthe volatility of the ,el1lori de of sodinm hithe presence of water at elcvated temperatures andthe degree of force and velocity with which the rapid transit of the steam conveyed away the unconverted chloride of sodium to a locality y where the temperature is too moderate to induce such Further, that althoughithesechanges might be sup posed to occur during thetran'sit or flight ofthe steam and chloride of sodium, yet the very moment the newly-formed soda, hydrochloric acid, and vapors of water attainedthe locality of a low temperature, the

; elements which had just been disengaged from each other would now reunite and reproduce the compoundsthatorigh all y existed.

It is also well to state that silicic acid-(and bases that comport themselveslike acids at exalted temper atures in the presence of soda and potassa) very much facilitated the desired transformation so far as chemical theories and affinities were concerned, but that intimate contact of the water, chloride of sodium, and

silica, or hase, could not be secured and maintained a sufficient length of time to accomplish the decomposition of more than four perv cent, of the material em ployed, for thegreasons already set. forth, namely, the volatilityrofthealkaline chlorides at. high temperatures in the presence of water orsteam. i

y I isithe ob'ectlof this invention to obviate these objections by theempldyment of hydrates which part with their water only at very elevated temperatures, so that thcsaid water maybe applied to the alkaline chlorides at an exalted temperaturcand in the nascent state. r

By the employment of these agencies,ha|nely, the l1 ydrates, the volatiliza't-ion of all the alkaline chlorides is obviatedat the temperatures necessary to effect theirl decomposition, with, however, the exception of chloride of ammonium. i

The hydrates of common occurrence and moderate cost, which retain their water at'cxalted temperatures are, the hydrated oxides of potassium, sodium, barium, strontium, calcium, magnesium, and aluminum.

7 a, l The agent I employ forthe decomposition of the alkaline chlorides in preferenceto all others, is the hydrated oxide of' aluminum, (alumina,) for-the reason that it exerts the behavior of an acid after having surrendered its water, and is then ready to combine with the caustic alkali the moment i t.-is formed, which action is necessary for the protection of the apparatns employed, on account of the destructive influence of caustic alkalies upon clay,,glass, iron, or other apparatua Alumina is a sufliciently strong acid in the presence of potash and soda at high temperatures to expel ca bonic acid from them, but at low heats the reverse is the case, as carbonic acid will displace alumina.

Alumina, in the presence of silicic acid at exalted temperatures, plays'the part of a powerful base.

Having now explained the principles upon which the invention depends, I will proceed to describe its practical application.

I first provide myself with a clay retortand suitable condensing apparatus. I

The apparatus now generally used will answer the sium with a sufiicicnt quantity of hydrate, bihydratc,

or terhydrato of alumina, (oxide of aluminum) to insure the complete decomposition of the alkaline chloride cmpl'oyed.

I next charge this mixture into the retort, and submit it to a temperature necessary to produce a continuous flow of hydrochloric acid from the retort to the condensing apparatus, where it is absorbed by the water, and is then-ready for market. I try to effect this transformation at aslow a temperature as poss-i-- "bl'e,- to prevent the formation of silicates by the action of the neWly formed alkali from the chloride upon the silica'in the clay retort; but I continue to apply the heat as long as the flow of hydrochloric acid is apparent, having in'the outset appropriated an abundance of the hydrate of alumina to secure the decomposition of all the ehloride.-

--When the foregoing operation 1s completed, Iwithdraw the product of aluminatc of soda or aluminatc of potassa from the retort, dissolve it in water, and precipitate the hydrate of alumina-with carbonic acid,

which leaves carbonate of soda or carbonate of potash in .solut-ion, depending upon whether alumnitate of soda or aluminate of potash is thelsubject bidecomposition. 

